Well, back to the great debate.
Back in December I got the Internet flaming of my life for the audacity to even offer a cold air intake. At that time you could only buy one and it was the worst design ever conceived. At least now your options are better. It seems like every few months we dive back into this subject and all three of us who stand to make any money off the topic will all tell you something different
*Smart Car Performance will tell you that since theirs draws air from close to the inlet scoop theirs is the best.
*I (Genius Parts) will tell you that since mine draws air from down low that mine is the best.
*And breathless will tell you that just putting their panel filter in is enough and theirs is the best.
Who's is really the best? To be honest both mine and Smart Car Performance are probably within a couple of HP and a couple of degree intake temp of each other. Mine is a little cheaper but there's comes in a bunch of colors.
In short, Buy which ever one you like better, we are kind of splitting hairs. They are just two different ways to get to the same end result, which is some extra power for your Smart. (probably about 4HP at the wheels)
I have to disagree a little about the noise thing. If you look at the air box that came in your Smart Car it is multiple chambers and piping with the object being less noise. You are replacing this with a product engineered to provide a less restricted flow of air into the throttle body. It's going to be a little louder on full throttle, you will actually be able to hear the air being sucked into the motor on either design.